Carlos Garnacho authored Jul 19, 2019 and Carlos Garnacho committed Feb 29, 2020

This is used by GDK and the X11 bits, but may also be used for
other initialization services we might need to run along with
Xwayland initialization.

However, as the -initfd argument in Xwayland is a fairly new
feature, add some meson build-time checks so that the feature
is handled transparently while allowing to explicitly set/unset
it.

GNOME/mutter!945